Logarithm -
For a number x, the power to which a given base number must be raised in order to obtain x. Written \log_b x. For example, \log_{10 1000 1000 and \log_2 16 16.
Wikipedia
The logarithm of a number to a given base is the power or exponent to which the base must be raised in order to produce that number. For example, the logarithm of 1000 to base 10 is 3, because 3 is the power to which ten must be raised to produce 1000: 10 = 1000. The logarithm of x to the base b is written logb(x) so that log10(1000) = 3.
OmegaWiki Dictionary
Ω
Logarithm The number by which a fixed number (the base) must be raised to produce a given number.